Effects loop noise

[knirirr]

Despite not knowing much about effects, I recently obtained a cheap reverb pedal (TC Electronics Skysurfer), which turns out to be quite fun for mucking about. If I plug my bass into the pedal and the pedal into the amp's normal input all is fine, but if I connect the pedal to the effects loop (Orange Terror Bass head) then the amount of noise is horrible - humming and hissing, and the pedal's sound when the effects are turned up seems to deteriorate.

My suspicion is that the amp is at fault, but it may be because, not being familiar with the use of effects, I'm not supposed to plug just one into the amp's effects loop. In either case it's a bit of a nuisance. Can anyone enlighten me?

[dannybuoy]

How old is the Terror Bass head?

I have one of the originals, and the DI output as well as the FX loop is hot as hell, far too much signal for most devices. Pedals are less likely to respond well to hot signals than rack units also. I believe they sorted the gain levels out on the newer ones (even before they discontinued them and then came out with a new model).

[knirirr]

Thanks. It’s one of the newer models with a clean switch on it, if fairly recent manufacture. If the problem is what you suspect, is there anything that can be done about it?

[dannybuoy]

Is the signal fine when the pedal is bypassed? If you turn it on but have the mix control all the way off, does turning the pedal on drop the volume and distort the signal? If so, then it's likely to be overloading the pedal. If it's a hum, like you might get from half unplugging a cable, then it might be something else.

[knirirr]

I’ll check on this tomorrow to be certain - IIRC the noise is bad even if the pedal is off. 

[pete.young]

The effects loop runs at line level and is aimed at line level equipment, like rack compressors and other studio gear.

Effects pedals are normally designed to run at a much lower instrument level. Some will work in a loop, many will not. Looks like you found another one that doesn't. There's probably nothing wrong with the amp.

I suggest you forget using the loop and put the effect in the line between the bass and the amp, and all will continue to be well.

[dannybuoy]

It's supposed to be a true bypass pedal, so it should be fine when bypassed. If the pedal is fine in front of the amp, this might suggest a problem with the amp or cables. The patch cables you were using - try each of them directly in the send/return to see if one of the cables is the cause?

[songofthewind]

My MarkBass combo drives effects very hard in the loop, causing distortion with some FX, even when jumpered internally to parallel. I reverted to using them in front.

[knirirr]

Looks like the cables are fine and the pedal is only noisy when turned on. Presumably I’ll need to plug it in directly (a minor nuisance) or buy a pedal that can handle it.